missing going up hill?

[GMhendricksbus]

Hello The Diesel Page People! My father inlaws truck is a 94 K2500 4x4,199,876 miles on the clock,to the best of knowledge the injectors and injection pump are factory! just replaced an over due fuel tank with that a filter and a up pump! the miss was there before the fixes and still remains!! checked all the fuel lines up too the injector pump no cracks or pin holes! the truck only misses going up hill when u get out of it or when u have the cruise on! going down the flat it doesnt miss a beat!! LOL!! any thoughts would be helpful!! Thanks!!

[JohnC]

Are you sure the lift pump is running when the engine is missing?

[GMhendricksbus]

No! and how are us suppose to check that when the truck is moving? would the ops be faulty even when the oil gauge works?? not trying to be rude! sorry if i come across like that! Ive read that the lift pump is controlled by the OPS! does the ops control the dash gauge? Thanks!!

[JohnC]

would the ops be faulty even when the oil gauge works??

Yes, completely separate circuits in the same box.

[More Power]

Like John said - a bad lift pump/oil prssure switch is the usual suspect for a missing under acceleration problem. A plugged (or partially plugged) fuel filter can also cause it or make it worse.

Jim

[GMhendricksbus]

checked the lift pump again! its vibrating sitting there idling! how could i test it while going down the road?? thanks!